Kensington Palace has issued a plea and a warning to world press and paparazzi who are going to “extreme lengths” and “crossing lines” to take pictures of the third in line to the throne, not to publish unauthorised images of the two-year-old, son of the Duke of Cambridge, Prince william

The Palace said it wants to “inform public discussion” on photography of children.

According to the statement, a small number of media organisations, mostly in Germany, France, Australia, New Zealand and the US, had published photos of Prince George in “unacceptable circumstances”.

However it said the “vast majority”, and all UK publications, had refused.

The palace says in recent months, photographers have:

Used long range lenses to photograph the Duchess of Cambridge playing with her son in private parks

Monitored the movements of Prince George and his nanny around London parks, as well as the movements of other household staff

Photographed the children of private individuals visiting the Duke and Duchess of Cambridge’s home

Pursued cars leaving family homes

Used other children to draw Prince George into view around playgrounds

Hidden on private property in fields and woodland locations around the duke and duchess’s Norfolk home

Obscured themselves in sand dunes on a rural beach to take photos of Prince George playing with his grandmother

Placed locations near the home of Catherine’s parents in Berkshire under steady surveillance

It said the most recent incident, which was last week, involved a photographer who was discovered by police lying down in the boot of a rented car attempting to shoot photos outside a children’s play area.

In the published letter, Kensington Palace communications secretary Jason Knauf said the prince had become the paparazzi’s “number one target”.

He said: “It is of course upsetting that such tactics – reminiscent as they are of past surveillance by groups intent on doing more than capturing images – are being deployed to profit from the image of a two-year-old boy.

“In a heightened security environment such tactics are a risk to all involved.

“The worry is that it will not always be possible to quickly distinguish between someone taking photos and someone intending to do more immediate harm.”

Mr Knauf said the duke and duchess wanted Prince George and his sister Princess Charlotte “to be free to play in public and semi-public spaces with other children without being photographed”.

They want to give their children a childhood that is “free from harassment and surveillance”, he said.